Hand tools of the type in question are known, for instance not only conventional hand tools for two-handed operation but also for example electrohydraulically operating hand tools of lighter construction for operation with only one hand. Such hand tools serve for example in the sanitary sector for pressing pipe connections, or else in the electrical sector for pressing cable lugs onto the ends of electric cables. With the lighter hand tools for use with only one hand, hydraulic forces of for example 3 tonnes are achieved. In this connection, reference is made for example to DE 10216213 A1 which United States counterpart is U.S. Pat. No. 7,421,877. The content of this patent application and accordingly its United States counterpart patent are is hereby incorporated in full in the disclosure of the present invention, including for the purpose of incorporating features of this patent application and accordingly its United States counterpart patent in the claims of the present invention.
In the case of the known hand tool, the working head is connected to the body unit by means of a thread. This, however, is only to allow any required changing of a working head to be performed, or maintenance work to be carried out. The working part is a pivotable pressing jaw, which can be moved under force by hydraulic movement of a piston associated with the working head against a pressing jaw that is for example fixed.
Apart from such hydraulically actuated hand tools, hand tools of this type actuated by an electric motor are also known. In this respect, reference is made for instance to DE 202006001301 U1 and DE 2709946 C2. Here, the working parts comprise pressing jaws, each of which is power-actuated.
In the case of the known hand tools, an infeed movement, that is to say powered actuation, of the working part is brought about by hydraulic pressure, or by for example a spindle adjustment by means of an electric motor. For this purpose, a first switching actuation with a switching button is required. Another movement of the working part, in particular a return movement after work has been performed, that is to say for example after completion of a pressing operation, often takes place automatically, to be specific in response to the triggering of a return valve in the case of a hydraulic device, or it must be triggered by further actuation of a lever or switch, the latter for instance in the case of an electrical device.
In particular in the case of difficult operating conditions for such a hand tool, for instance on construction sites or in the mining sector, efforts are being made to find a form of actuation that involves definite and clear handling.